In a new study on women over the age of 50 years from the United States, investigators from the University of Iowa in Iowa City, IA have found that overindulging in fried foods can increase a person's risk of death from multiple causes.

The researchers also looked at which fried foods are likely to be the most dangerous for health. A study paper reporting the findings now appears in The BMJ.

The research team worked with data from 106,966 women between the ages of 50 and 79 years who joined the Women's Health Initiative (WHI) study between 1993 and 1998. The researchers had access to follow-up information through to February 2017.

Over the course of the study, 31,588 participants died. Of these deaths, 9,320 were due to heart problems, 8,358 were cancer-related, and 13,880 had associations with other causes.

8 per cent higher all-cause death risk

As part of the WHI study, the participants filled in questionnaires detailing their dietary habits. They reported on their specific intake of a variety of fried foods and their total consumption of these foods, which the researchers split into three categories:

fried chicken

fried fish, fish sandwich, and fried shellfish, such as shrimp or oysters

other fried foods, such as french fries, tortilla chips, or tacos

The research team's analysis confirmed that there was a correlation between eating fried foods on a regular basis and an increased risk of death from any cause. The association was also strong for death relating to heart problems.

After accounting for modifying factors, including lifestyle, diet quality, income, and education level, the investigators found that participants who reported eating at least one serving of fried food per day had an 8 per cent higher risk of death than those who did not eat fried foods.

The researchers then looked at the effect of specific fried foods. They found that eating at least one serving of fried chicken per day led to a 13 per cent heightened risk of death from all causes and a 12 per cent higher risk of death relating to heart problems compared with eating no fried foods at all.

Eating at least one serving of fried fish or shellfish a day led to a 7 per cent increase in the risk of death from any cause and a 13 per cent higher risk of death from heart-related problems.

However, the research team did not identify a link between eating fried foods and the risk of cancer-related death.

A modifiable risk factor

The investigators also note that the women who were most likely to consume fried foods on a regular basis were in the younger age range (50–65 years old). They also tended not to be white and to have lower education levels, a lower income, and an overall poorer quality diet. Many of them were also smokers.

Following their present findings, the study authors conclude that: "Reducing the consumption of fried foods, especially fried chicken and fried fish/shellfish, may have clinically meaningful impact across the public health spectrum."

However, they warn that their results may not apply across different populations because their research was an observational study focusing specifically on women from the U.S.

Moreover, the researchers acknowledge that, even though they accounted for many potential modifying factors in their study, it remains possible that there may be "unidentified confounders" that they did not include in their analysis.

Still, they note that in this study, they "have identified a risk factor for cardiovascular mortality that is readily modifiable by lifestyle."